Insert type drill bit



Dec. 29, 1964 R. D. YORK INSERT TYPE DRILL BIT 2 Sheets-Sheet 1 Filed Sept. 12, 1961 Raymond 0 York INVENTOR.

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Dec. 29, 1964 R. D. YORK INSERT TYPE DRILL BIT 2 Sheets-Sheet 2 Filed Sept. 12, 1961 Raymond D. York l N VEN TOR. m WW am@ United States Patent() 3,163,245 lNSERT TYPE DRILL BlT Raymond D. York, San Angelo, Tex., assigner to Walton Hale, El Paso, Tex. Filed Sept. 12, 1961, Ser. N 137,659 6 Claims. (Cl. 17E- 408) This invention comprises a novel and useful insert type drill bit and more particularly pertains to a drill bit construction having longer life and a greater effectiveness for drilling well bores particularly in hard rock of the cavernous type.

It is well known in the drilling art and particularly in the drilling of deep well bores that the operation of the drill must be discontinued from time-to-time in order to resharpen or replace the worn teeth of a drill or substitute a new drill when this condition occurs. Inasmuch as the body of the drill is still ht for further service, it is obviously uneconomical to discard the complete drill. On the other hand, a serious monetary loss not to mention other undesirable conditions occur when it is necessary to suspend the drilling operation for the purpose of withdrawing the drill from the well bore and reconditioning or replacing the drill bit or the teeth thereof. Further,

in drilling through hard rock and of a character having cavernous regions therein, when the drill bit breaks through the overlying material into such cavernous region, frequently due to the incline of the formation at the bottorn of the `open space penetrated by the drill bit the drill will strike and engage only at one portion thereof. Due to the weight of the drill, this frequently results in the teeth at that portion of the drill bit being embedded in the formation to too great a depth so that upon the turning moment being applied to the drill by the usual rotary table at the surface, the teeth thus excessively embedded :L-

tend to break olf or at least wear unduly rapidly.

It is therefore the primary object of this invention to provide a drill bit construction which will satisfactorily overcome the aforementioned difficulties.

A further important object of the invention is to provide a drill bit construction having upon the cutting face of the drill body a firmly secured annulus or ring or attachment with a flat lower annular surface upon which insert drilling elements constituting drill teeth are secured and embedded, the ring serving as a carrier for the insert teeth, as a guage means limiting penetration of the teeth into the ground thus preventing excessive penetration of the teeth, and as a stabilizing and guide Vmeans for the drill body in the well bore.

Another object of the invention is to provide a drill bit construction in which a conventional type of rock drill having the usual centrally disposed dependent cutting teeth has attached thereto upon a shoulder means comprising shoulders formed at the peripheral portion of the cutting face of the drill an annulus to which are secured replaceable insert teeth.

Yet another purpose of the invention is to provide a drill bit construction in which conventional drills may be readily modified by providing thereon and securing rigidly thereto a ring comprising both a gauge means to limit penetration of the drill teeth, a support for a series of replaceable insert teeth and a stabilizer and guide for the drill body in the well bore.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE l is a View in vertical section through a portion of an earth formation showing the drilling of a well bore therein in accordance with the drill bit construction ice of this invention, the showing in full lines being that of normal drilling operations while in ydotted lines is shown the operation yof this invention upon drilling into cavernous portions of the formation;

FIGURE 2 is an end elevational view from the lower end of the drill bit construction of this invention;

FIGURE 3 is a vertical central sectional view through the drill bit, being taken substantially upon the plane indicated by the section line 3 3 of FIGURE 2; and

FIGURE 4 is an exploded perspective view of the drill bit, the gauge and mounting ring and the insert drilling elements carried by the latter.

Referring first to FIGURE l, it will be observed that the numeral lil indicates a portion of a formation into which is being drilled a well bore l2 by means of the usual drilling string 14 lhaving at the lower end thereof a drill bit construction 16 in accordance with the present invention. As suggested in FIGURE l, the well bore is continued down into the formation until it penetrates into a cavern or crevasse 18 through which it is desired to continue the well bore as indicated in dotted lines at Ztl. As the drill bit breaks through the upper wall or surface 22 of the cavern or crevasse, it will drop until it engages the inclined bottom wall 24 thereof. In conventional bits, when this condition occurs, the weight of the drilling string is borne entirely by a relatively few of the teeth which first engage the surface 24 so that these teeth may become embedded too deeply, thus taking too big a bite from the rock formation thereby breaking the teeth or causing serious damage thereto.

The drill bit construction of the present invention, as shown in FIGURES 3 and 4, comprises the usual drill body 39 having an externally threaded upwardly and inwardly tapered neck 32 by which it is removably secured to the correspondingly tapered internal thread of the lowermost section or drilling collar of the drilling string 14. As will be noted, the stern 32 is hollow having an axial passage 34 therethrough by means of which air or the usual drilling fluid is circulated downwardly through the drill string and drill bit, then across the bottom wall of the well bore and then upwardly of the well bore in the annular space between the latter and the drilling string to the surface.

Circumferentially spaced, radially extending and downwardly projecting drill teeth 36 are provided upon the lower or cutting face of the drill bit. Since these teeth may be of any conventional construction, a further description of the same is deemed to be unnecessary. In accordance with this invention, however, the peripheral portion of the cutting face of the drill body is provided with notches or shoulders 38 which lie in a common plane which is transverse to and perpendicular to the longitudinal axis of the drill body. Seated upon the shoulders 3S is a ring or annulus itlwhich as shown in FIGURE 3 is iixedly secured thereto as by welding 42. Thisannulus is of suilicient size and has a central opening 44 therethrough of sufficient size to surround the previously mentioned teeth 36 which latter project downwardly below the annulus to provide the axial or central or pilot portion of the drill. Preferably the cylindrical exterior surface of the annulus projects radially outwardly beyond the body'Stl as shown in FIGURES l and 3 in order to thus constitute a stabilizing and guide means for holding the drill body centrally in the well bore and in straight alinement with the latter.

The lower surface of the ring or annulus 4t) constitutes a ilat annular surface 46 which constitutes a gauging surface for the drill bit construction as set forth hereinafter. Formed at spaced intervals circumferentially of the surface 46 are a series of downwardly projecting lugs 48 together with radially extending notches Sil formed at the vertical face 52 of these lugs. A series of insert cutting principles of the invention.

l enables a relatively small number of drilling elements 54 of extremely hard cutting or abrasive material to be j utilized since they are firmly supported in the notches 50 and against they face 52 of the lug 48. Thus, a relatively expensive material can be employed for the cutting ele-V ments 54 which would be not feasible for the entire structure of a drill bit. Y

It will be further understood that when replacement of the elementsV 54 becomes necessary, they can readilyv be removed from the ring 40 and replaced, or the entire ring may be removed from its seat upon the shoulders 38 Vof the drill body 2()k and replaced withranother sub-assembly of a ring withk the cutting elements mounted therein.

The ring is so spaced with regard to the'drill teeth 36V Y center the drill with respect to the sides of the well bore.

However, when the drill breaks into a cavernous or iissured formation 1S, and the drill ydrops downwardly as shown in the dottedy line position, the engagement of the flat surface 46 upon the surface 24 of the ssure will limit penetration of the teeth of the drillbit so that they will not take too great a bite and thus be broken or damaged. However, as the drilling continues, and the'drill y being maintained in its desired attitude with respect to the axis of the well bore, the drilling of the'well bore will be resumed as at 20 in true alinement with the Well bore l2.v

It willbe observed that the ring 4i) thus serves-a number of important functions. It provides a readily replaceable sub-assembly by which new sets of insert teeth may Y be applied tothe drill body 30. In addition, it constitutes a gauge limiting penetration of the teeth into the formation so as to prevent excessive penetration with Vresultant breakage of the teeth. Still further, it constitutes a centralizer or stabilizer for the drill body inthe well bore ensuring proper positioning of the drill-'in the bore. Still further, as shown by the passages indicated at 56 in FIG- URE 3, there is provided a clearance between the inside perimeter within the opening .44 of the ring and the outer surface of the teeth yof the drill body 30 to permit ready upward flow of drilling fluid from the bottom of the wellbore past the bit construction and into the annulus surrounding the drilling string.

The foregoing is considered as illustrative only of the Further, since numerous modifications and changes will readily occur Vto those skilled in the art, it is not desired to limit the invention to the exact construction and operation showny and described, and accordingly alltsuitable modifications and.

equivalents may bei resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A drill bit construction comprising a drill body having a lower end provided with a plurality of axially and radially extending wings with pilot teeth projecting downv wardly therefrom, peripherally extending shoulder means on said wings surrounding and recessed into the radially outward portions of said wings, saidshoulder means including planar horizontal and depending vertical convex surfaces, annular means comprising a ring having flat top and bottom surfaces and cylindrical outer and inner surfaces, said ring top and innerl surfaces being respectively seated upon and secured to said shoulder means horizontal and vertical surfaces, said ring'inner surface being spaced from some of said pilot teeth and thereby providing fluid llow passagesbetween saidV ring and said body, insert elements comprising drill teeth secured to and projecting downwardly from said ring bottom surface. Y

2. The combination of claim l wherein said horizontal surfaces are flat andcoplanar, said ring top surface including flat portions each seated upon a horizontal surface over the entire area of the latter, said ring inner surface engaging Veach vertical surface overthe entire circumferential extent of the latter.

3. The combination of claim l wherein said bottom surface has a pluralityrof downward projections there- Y Vfrom provided each with a plane vertical face, a plurality of notches extending upwardly into said ring from said bottom surface and each'against a projection, said drill teeth being each seated and secured yin a notch and having `a vertical face disposed'in face-to-face engagement with an associated, projection face.

4. The combination of lclaim l wherein said outer surface is of greater diameter than that of said drill body Y and wings and constitutes the sole means of engagement with the Wall of a well bore.

5. The combination of claim l including axially projecting cutting elements carried'by said ring and projectl References Cited bythe Examiner Y UNITED VVSTATES PATENTS 1,582,332 4/26 Brutus 175-408 X 1,803,267 4/31 McCloskey 175-410 X 2,267,833 12/41 McMahan 175-408 X 2,749,101 6/56 Goodrich et al 175-394 X 6/56 Goodrich 1-75-394 X j Y FOREIGN PATENTS 1,091,958 L11/60 Germany. BENJAMIN BENDETT, Primm Examiner. 

1. A DRILL BIT CONSTRUCTION COMPRISING A DRILL BODY HAVING A LOWER END PROVIDED WITH A PLURALITY OF AXIALLY AND RADIALLY EXTENDING WINGS WITH PILOT TEETH PROJECTING DOWNWARDLY THEREFROM, PERIPHERALLY EXTENDING SHOULDER MEANS ON SAID WINGS SURROUNDING AND RECESSED INTO THE RADIALLY OUTWARD PORTIONS OF SAID WINGS, SAID SHOULDER MEANS INCLUDING PLANAR HORIZONTAL AND DEPENDING VERTICAL CONVEX SURFACES, ANNULAR MEANS COMPRISING A RING HAVING FLAT TOP AND BOTTOM SURFACES AND CYLINDRICAL OUTER AND INNER SURFACES, SAID RING TOP AND INNER SURFACES BEING RESPECTIVELY SEATED UPON AND SECURED TO SAID SHOULDER MEANS HORIZONTAL AND VERTICAL SURFACES, SAID RING INNER SURFACE BEING SPACED FROM SOME OF SAID PILOT TEETH AND THEREBY PROVIDING FLUID FLOW PASSAGES BETWEEN SAID RING AND SAID BODY, INSERT ELEMENTS COMPRISING DRILL TEETH SECURED TO AND PROJECTING DOWNWARDLY FROM SAID RING BOTTOM SURFACE. 